Problem: $3ab + 6ac - 5a - 5 = -5b - 10$ Solve for $a$.
Answer: Combine constant terms on the right. $3ab + 6ac - 5a - {5} = -5b - {10}$ $3ab + 6ac - 5a = -5b - {5}$ Notice that all the terms on the left-hand side of the equation have $a$ in them. $3{a}b + 6{a}c - 5{a} = -5b - 5$ Factor out the $a$ ${a} \cdot \left( 3b + 6c - 5 \right) = -5b - 5$ Isolate the $a$ $a \cdot \left( {3b + 6c - 5} \right) = -5b - 5$ $a = \dfrac{ -5b - 5 }{ {3b + 6c - 5} }$ We can simplify this by multiplying the top and bottom by $-1$. $a= \dfrac{5b + 5}{-3b - 6c + 5}$